Acoustic change complex for assessing speech discrimination in normal-hearing and hearing-impaired infants.

Objective: This study examined (1) the utility of a clinical system to record acoustic change complex (ACC, an event-related potential recorded by electroencephalography) for assessing speech discrimination in infants, and (2) the relationship between ACC and functional performance in real life.

Methods: Participants included 115 infants (43 normal-hearing, 72 hearing-impaired), aged 3-12 months. ACCs were recorded using [szs], [uiu], and a spectral rippled noise high-pass filtered at 2 kHz as stimuli.

Automated cortical auditory response detection strategy.

This study describes a new automated strategy to determine the detection status of an electrophysiological response. Response, noise and signal-to-noise ratio of the cortical auditory evoked potential (CAEP) were characterised. Detection rules were defined: when to start testing, when to conduct subsequent statistical tests using residual noise as an objective criterion, and when to stop testing.

Is cortical automatic threshold estimation a feasible alternative for hearing threshold estimation with adults with dementia living in aged care?

This study explored the feasibility of cortical automatic threshold estimation (CATE), a fully automated late auditory evoked potential (AEP) test, as an alternative to pure-tone audiometry for hearing threshold estimation for adults with dementia living in aged care. A single group cross-sectional study was conducted. Participants' dementia severity was determined through the Clinical Dementia Rating scale.

Restoration of cortical symmetry and binaural function: Cortical auditory evoked responses in adult cochlear implant users with single sided deafness.

Background: Cochlear implantation for single-sided deafness (SSD) is the only treatment option with the potential to restore binaural hearing cues. Significant binaural benefit has been measured in adults by speech in noise and localisation tests, who receive a cochlear implant for SSD, however, little is known on the cortical changes that help provide this benefit. In the present study, detection of sound in the auditory cortex, speech testing and localisation was used to investigate the ability of a cochlear implant (CI) to restore auditory cortical latencies and improve binaural benefit in the adult SSD population.

Recording Obligatory Cortical Auditory Evoked Potentials in Infants: Quantitative Information on Feasibility and Parent Acceptability.

Objectives: With the advent of newborn hearing screening and early intervention, there is a growing interest in using supra-threshold obligatory cortical auditory evoked potentials (CAEPs) to complement established pediatric clinical test procedures. The aim of this study was to assess the feasibility, and parent acceptability, of recording infant CAEPs.

Design: Typically developing infants (n = 104) who had passed newborn hearing screening and whose parents expressed no hearing concerns were recruited.

Clinicians' views of using cortical auditory evoked potentials (CAEP) in the permanent childhood hearing impairment patient pathway.

To obtain clinicians' views on the use of cortical auditory evoked potentials (CAEP) in the clinical pathway. A questionnaire aimed at clinicians who use the HEARLab system with the Aided Cortical Assessment (ACA) Module. Results compared for Australians (where HEARLab produced) to other countries.

The frequency-following response as an assessment of spatial processing.

It is important to detect children with difficulties distinguishing speech-in-noise early. Prompt identification may be assisted by an evoked potential. The aims of the present study were: 1) to evaluate the frequency-following response (FFR) as a measure of binaural processing and spatial listening and, 2) to investigate the relationship between the FFR and a behavioural measure of binaural processing and spatial listening.

Effects of lifetime noise exposure on the middle-age human auditory brainstem response, tinnitus and speech-in-noise intelligibility.

Recent animal studies have shown that the synapses between inner hair cells and the dendrites of the spiral ganglion cells they innervate are the elements in the cochlea most vulnerable to excessive noise exposure. Particularly in rodents, several studies have concluded that exposure to high level octave-band noise for 2 h leads to an irreversible loss of around 50% of synaptic ribbons, leaving audiometric hearing thresholds unaltered. Cochlear synaptopathy following noise exposure is hypothesized to degrade the neural encoding of sounds at the subcortical level, which would help explain certain listening-in-noise difficulties reported by some subjects with otherwise 'normal' hearing.

Clinically recorded cortical auditory evoked potentials from paediatric cochlear implant users fitted with electrically elicited stapedius reflex thresholds.

Objectives: This study aimed to objectively evaluate access to soft sounds (55 dB SPL) in paediatric CI users, all wearing MED-EL (Innsbruck, Austria) devices who were fitted with the objective electrically elicited stapedius reflex threshold (eSRT) fitting method, to track their cortical auditory evoked potential (CAEP) presence and latency, and to compare their CAEPs to those of normal-hearing peers.

Methods: Forty-five unilaterally implanted, pre-lingually deafened MED-EL CI users, aged 12-48 months, underwent CAEP testing in the clinic at regular monthly intervals post switch-on. CAEPs were recorded in response to short speech tokens /m/, /g/ and /t/ presented in the free field at 55 dB SPL.

Remediation of spatial processing disorder (SPD).

Objective: To determine the efficacy of deficit-specific remediation for spatial processing disorder, quantify effects of remediation on functional listening, and determine if remediation is maintained.

Design: Participants had SPD, diagnosed using the Listening in Spatialised Noise-Sentences test. The LiSN and Learn software was provided as auditory training.

An automatic algorithm for blink-artifact suppression based on iterative template matching: application to single channel recording of cortical auditory evoked potentials.

Objective: Artifact reduction in electroencephalogram (EEG) signals is usually necessary to carry out data analysis appropriately. Despite the large amount of denoising techniques available with a multichannel setup, there is a lack of efficient algorithms that remove (not only detect) blink-artifacts from a single channel EEG, which is of interest in many clinical and research applications. This paper describes and evaluates the iterative template matching and suppression (ITMS), a new method proposed for detecting and suppressing the artifact associated with the blink activity from a single channel EEG.

Consequences of Early Conductive Hearing Loss on Long-Term Binaural Processing.

Objectives: The aim of the study was to investigate the long-term effects of early conductive hearing loss on binaural processing in school-age children.

Design: One hundred and eighteen children participated in the study, 82 children with a documented history of conductive hearing loss associated with otitis media and 36 controls who had documented histories showing no evidence of otitis media or conductive hearing loss. All children were demonstrated to have normal-hearing acuity and middle ear function at the time of assessment.

Effects of spectral smearing on performance of the spectral ripple and spectro-temporal ripple tests.

The main aim of this study was to use spectral smearing to evaluate the efficacy of a spectral ripple test (SRt) using stationary sounds and a recent variant with gliding ripples called the spectro-temporal ripple test (STRt) in measuring reduced spectral resolution. In experiment 1 the highest detectable ripple density was measured using four amounts of spectral smearing (unsmeared, mild, moderate, and severe). The thresholds worsened with increasing smearing and were similar for the SRt and the STRt across the three conditions with smearing.

Clinical Experience of Using Cortical Auditory Evoked Potentials in the Treatment of Infant Hearing Loss in Australia.

This article presents the clinical protocol that is currently being used within Australian Hearing for infant hearing aid evaluation using cortical auditory evoked potentials (CAEPs). CAEP testing is performed in the free field at two stimulus levels (65 dB sound pressure level [SPL], followed by 55 or 75 dB SPL) using three brief frequency-distinct speech sounds /m/, /ɡ/, and /t/, within a standard audiological appointment of up to 90 minutes. CAEP results are used to check or guide modifications of hearing aid fittings or to confirm unaided hearing capability.

Cortical Auditory Evoked Potentials in (Un)aided Normal-Hearing and Hearing-Impaired Adults.

Cortical auditory evoked potentials (CAEPs) are influenced by the characteristics of the stimulus, including level and hearing aid gain. Previous studies have measured CAEPs aided and unaided in individuals with normal hearing. There is a significant difference between providing amplification to a person with normal hearing and a person with hearing loss.

Cortical Auditory-Evoked Potentials in Response to Multitone Stimuli in Hearing-Impaired Adults.

Purpose: To determine if one-octave multitone (MT) stimuli increase the amplitude of cortical auditory-evoked potentials (CAEPs) in individuals with a hearing loss when compared to standard pure-tone (PT) stimuli and narrow-band noise (NBN).

Research Design: CAEPs were obtained from 16 hearing-impaired adults in response to PT and MT auditory stimuli centered around 0.5, 1, 2, and 4 kHz and NBN centered around 1 and 2 kHz.

Bigger Is Better: Increasing Cortical Auditory Response Amplitude Via Stimulus Spectral Complexity.

Objective: To determine the influence of auditory stimuli spectral characteristics on cortical auditory evoked potentials (CAEPs).

Design: CAEPs were obtained from 15 normal-hearing adults in response to six multitone (MT), four pure-tone (PT), and two narrowband noise stimuli. The sounds were presented at 10, 20, and 40 dB above threshold, which were estimated behaviorally beforehand.

Estimating Hearing Thresholds in Hearing-Impaired Adults through Objective Detection of Cortical Auditory Evoked Potentials.

Background: Hearing threshold estimation based on cortical auditory evoked potentials (CAEPs) has been applied for some decades. However, available research is scarce evaluating the accuracy of this technique with an automated paradigm for the objective detection of CAEPs.

Purpose: To determine the difference between behavioral and CAEP thresholds detected using an objective paradigm based on the Hotelling's T² statistic.

Least-squares (LS) deconvolution of a series of overlapping cortical auditory evoked potentials: a simulation and experimental study.

Objective: To evaluate the viability of disentangling a series of overlapping 'cortical auditory evoked potentials' (CAEPs) elicited by different stimuli using least-squares (LS) deconvolution, and to assess the adaptation of CAEPs for different stimulus onset-asynchronies (SOAs).

Approach: Optimal aperiodic stimulus sequences were designed by controlling the condition number of matrices associated with the LS deconvolution technique. First, theoretical considerations of LS deconvolution were assessed in simulations in which multiple artificial overlapping responses were recovered.

Deconvolution of overlapping cortical auditory evoked potentials recorded using short stimulus onset-asynchrony ranges.

Objective: The first aim of this study is to validate the theoretical framework of least-squares (LS) deconvolution on experimental data. The second is to investigate the waveform morphology of the cortical auditory evoked potential (CAEP) for five stimulus onset-asynchronies (SOAs) and effects of alternating stimulus frequency in normally hearing adults.

Methods: Eleven adults (19-55 years) with normal hearing were investigated using tone-burst stimuli of 500 and 2000 Hz with SOAs jittered around 150, 250, 450, and 850 ms in a paired-interval paradigm with fixed or alternating stimulus frequency.

Cortical auditory-evoked potentials (CAEPs) in adults in response to filtered speech stimuli.

Background: Previous studies have demonstrated that cortical auditory-evoked potentials (CAEPs) can be reliably elicited in response to speech stimuli in listeners wearing hearing aids. It is unclear, however, how close to the aided behavioral threshold (i.e.

Least-squares deconvolution of evoked potentials and sequence optimization for multiple stimuli under low-jitter conditions.

Objective: Rapid presentation of stimuli in an evoked response paradigm can lead to overlap of multiple responses and consequently difficulties interpreting waveform morphology. This paper presents a deconvolution method allowing overlapping multiple responses to be disentangled.

Methods: The deconvolution technique uses a least-squared error approach.

The relationship between cortical auditory evoked potential (CAEP) detection and estimated audibility in infants with sensorineural hearing loss.

Objective: To determine the effectiveness of objective statistical detection in CAEP testing to evaluate audibility in young infants with sensorineural hearing loss.

Design: CAEP recordings to speech-based stimuli were made at three presentation levels (55, 65, or 75 dB SPL) when a group of hearing-impaired infants were either aided or unaided. Later-obtained behavioral audiograms were used as the gold standard against which to evaluate the accuracy of the automatic detection of the presence/absence of CAEP responses.

Sensitivity of cortical auditory evoked potential detection for hearing-impaired infants in response to short speech sounds.

Cortical auditory evoked potentials (CAEPs) are an emerging tool for hearing aid fitting evaluation in young children who cannot provide reliable behavioral feedback. It is therefore useful to determine the relationship between the sensation level of speech sounds and the detection sensitivity of CAEPs, which is the ratio between the number of detections and the sum of detections and non-detections. Twenty-five sensorineurally hearing impaired infants with an age range of 8 to 30 months were tested once, 18 aided and 7 unaided.

Latencies of auditory steady-state responses recorded in early infancy.

Multiple-stimulus auditory steady-state responses (ASSRs) were assessed in 111 ears of 70 infants between -4 and 19 weeks of age at risk for hearing loss. ASSR thresholds obtained in infants with normal hearing (n = 69 ears) were compared with normal adult ASSR thresholds (n = 32 ears), and the linear relation between ASSR thresholds and behavioral thresholds (BHTs) was investigated in normal-hearing and hearing-impaired infants (n = 79 ears). Furthermore, latency estimates of significant responses to stimuli of 50 dB SPL were compared between the normal-hearing infants (n = 171 data points) and adults (n = 124 data points) and developmental changes in latency were evaluated within the infant group.